This invention relates to a method of coating glass with a silicon-containing coating, and to silicon-coated glass so produced, and is an improvement in the method and product of our U.S. Pat. No. 4,019,887.
In U.S. Pat. No. 4,019,887 there is described and claimed a method comprising moving the glass past a coating station while the temperature of the glass is at least 400.degree. C. supplying silane-containing gas to the coating station; releasing the gas close to the hot glass surface at a substantially constant pressure across the glass surface into a hot zone in which the gas is heated, which zone opens towards and extends across the glass surface so that the silane pyrolyses depositing a silicon-containing coating on the glass surface, and maintaining non-oxidising conditions in said hot zone. The glass so produced has a substantially uniform silicon coating and has good solar control properties and a pleasing appearance.
It has now been found that by adding an electron-donating compound to the silane-containing gas which is released close to a hot glass surface, the alkali-resistance of the silicon coating on the glass is improved.
It is known from the paper "Reactions of Silane with Unsaturated Hydrocarbons" by David G. White and Eugene G. Rochow, Journal of the American Chemical Society Vo. 76, pages 3887 to 3902, that during the production of alkylsilanes by the reaction in a heated tube over a three hour period of a silane with ethylene or acetylene, a thin layer of silicon was deposited on the inner surface of the heated tube through which the gaseous reactants were being circulated.
It is a main object of the present invention to employ the discovery that the presence of an electron-donating compound imparts alkali-resistance to a silicon coating on glass.